1. Field of the Invention
The present invention relates to a hard carbon film-coated substrate which has a hard carbon film formed on a substrate surface and to a method for fabricating the hard carbon film-coated substrate. The present invention further relates to a method for providing a hard carbon film on a substrate, more particularly to a method for providing a protective film such as on inner and outer blades of an electric shaver, magneto-optical disks, thin film magnetic heads and surface acoustic wave (SAW) devices; an antireflection film for lithography; a protective film on sliding surfaces of compressors; or a hard carbon film such as on constituent layers of solar batteries, decorative articles and optical parts.
2. Description of Related Art
It has been conventionally known that the formation of a diamond-like carbon film directly on a substrate results in poor adhesion between the diamond-like carbon film and the substrate. In order to overcome such a disadvantage, proposals have been made which interpose a Si interlayer between the diamond-like carbon film and the substrate (see, for example, Japanese Patent Laying-Open Nos. 2-182880(1990), 3-115572(1991) and 1-138611(1989)).
Japanese Patent Laying-Open Nos. 7-41386(1995) and 7-316818(1995) disclose that the adhesion between a hard carbon film and a substrate can be improved by providing an interlayer of Si, Ru or Ge therebetween even when the substrate is made of a metal or an alloy principally formed of Ni or Al, suitably used such as for an electric shaver blade, or of a stainless steel.
The above-described prior art interlayer is effective in improving adhesion and peel resistance between the substrate and the hard carbon film, e.g. the diamond-like carbon film if interposed therebetween. However, considering the technological abundance in the field and applicability to various technological situations, there still remains a need for the other type of interlayer which is also capable of improving the adhesion and peel resistance between the substrate and the hard carbon film.
The above-described conventional interlayers have been formed by vapor phase epitaxial methods such as a sputtering method and a plasma CVD method. This requires that the thickness of the interlayer be made greater, or alternatively, the substrate position be changed during the interlayer formation if the substrate has a complicated three-dimensional configuration.